262 University of California Publications in Zoology (VoL. 23 
Pinnixa occidentalis Rathbun 
Plate 42, figures 5 and 6 
Pinnixa occidentalis Rathbun, Proc. U. 8. Nat. Mus., 16, 248, 1893 (part: 
except specimen from San Diego); Holmes, Occas. Papers Calif. Acad. 
Sci., 7, 89, 1900; Rathbun, H. A. E., 10, 187, pl. 7, fig. 4, pl. 9, figs. 6, 
6a, 1904 (part: except specimens from Cape Fox) ; Weymouth, Stanford 
Univ. Publ., Univ. Ser., no. 4, text fig. 3, 1910; Rathbun, Bull. U. S. 
Nat. Mus., 97, 155, text fig. 96, pl. 34, fig. 1, 1918. 
Pinnixa californiensis Rathbun, Proc. U. S. Nat. Mus., 16, 249, 1893; 
Holmes, Oceas. Papers Calif. Acad. Sci., 7, 90, 1900; Rathbun, H. A. E., 
10, 187, pl.’7, fig. 3, 1904; Weymouth, Stanford Univ. Publ., Univ. Ser., 
no. 4, 56, 1910 (part: except young female from Pacific Grove). 
a ; b 
Fig. 156. Pinnizxa occidentalis, J; a, dorsal view, X 114; b, chela, X 3% 
(after Rathbun). 
Characters.—Carapace more or less uneven, about twice as wide as long, 
occasionally a little more or a little less, with a single bilobed cardiac crest, 
anterolateral margin marked by a sharp, more or less granulated ridge running 
from the orbit diagonally outward and backward, crossing the hepatic region, 
and forming the anterolateral margin of the carapace. Chelipeds stout, setose; 
palm broad, flat, shining on outside, immovable finger short, markedly deflexed, 
prehensile edge with a stout tooth in the middle and a small one near the tip; 
movable finger much curved, sometimes with a tooth in the middle. Ambulatory 
legs setose; first pair shorter than the chelipeds, weak; second pair longer and 
stronger than the first; third pair very long and strong, especially the merus, 
propodus longer than wide; fourth pair intermediate in length between the first 
and second; dactyli as long as the propodi. 
Dimensions.—Type, male: length of carapace 9.5 mm., width 19.5 mm.; female: 
length of carapace 10.5 mm., width 20.5 mm. 
Type Locality—South of Unimak Island, Alaska. 
Distribution.—Unalaska to Magdalena Bay, Lower California. Shallow water 
to 238 fathoms. 
Remarks.—Cardiae ridge blunter in female than in male, immovable finger 
longer, third ambulatory leg shorter and wider, about two and one-half times as 
long as wide. Specimens vary in the proportion of length to width of carapace, 
in the prominence of cardiac ridge, in the direction of the margins of the second 
abdominal segment of the male, in the length of the immovable finger of the 
male (Rathbun). Commensal in the burrows of the gephyrean worm JHchiurus 
(Kineaid, from Rathbun). 
Biological Survey of San Francisco Bay.—Pinmca occidentalis was 
only taken outside the bay at three stations, D 5785, 5788, and 5789, 
